Apparatus for use in forming pittsburgh joints



y 1939- G. E DEMMIN 2,159,784

APPARATUS FOR USE J IN FORMING PITTSBURGH JOINTS Filed July 28, 1937Patented May 23, 1939 UNITED STATES PATENT OFFICE APPARATUS FOR USE INFORMING Prr'rs- BURGH JOINTS George Edwin Demmin, Peoria, n1.

8 Claims.

ing so called Pittsburgh joints, said invention contemplating a specialmachine constructed for the named purpose, or an attachment to the wellknown brakef employed in sheet-metal-benda ing operations.

.The main object of the invention is to pro- "wvide an apparatus forsheet metal bending by,

zti while, reducing many laborious handling opera- That the inventionmay be fully understood the appended drawing is provided wherein;

(Figure 1 is a transverse sectional elevation of gg parts of anapparatus involving my invention showing an inserted sheet metal partasthe work to .be acted upon.

Figure 1 shows in perspective part of an abutment member illustrated inFigurel. "36"?" Figure 2 is a simil'ar to Figure 1 showing one ftheparts of, the apparatus in a different position-ffor acting upon theinsertedwork.

igures corresponds to the earlier figures, particularly Figure 1 whereina part of the, appara- 1 3o tus involved in the invention is shownashaving been manipulated for acting upon the work. .,Figure 4 correspondsto Figure 1 with the work infa"different position after being acted uponfor applying pressure thereto as a finishing operaon. i

Figures 5, 6 and 7 show the various forms of the work resulting fromoperationsthereon and treated shown in Figures 2, 3 and4 respective-Figural; illustrates in perspective a sheet metal elbow merely to bestgive an understanding of F i the use of the type of joint herein named.

Sheet metal workers are familiar with the 50 many tedious operationsnecessary in forming a joint by hand and the more or lessimperfectjlyrfinished product, aswell as the considerable fwork. Q

Itis with this view that the apparatus now This invention relates toapparatus for 'formbending rail 2. rail 2 and the surface 8' of themember is spaced 5* correspond in the order given with the work asamount of time required to turn out a given piece Application July 28,1937, Serial No. 156,096

to be described has been provided whereby the joint may be quickly,easily and perfectly provided.

In order to make the invention readily understood the' essential partsof a brake of any 5- ordinary type are herein illustrated, the samebeing shown in transverse section, wherein I designates a support suchas a part of a bench or table to receive upon its top surface the workto be acted upon indicated at A, 2 representing 10 a member known as abending rail, this usually lying at an angle of substantially 45 to thetop surface of said bench I which by means of suitable guides andoperating means not shown,

is raised and lowered as employed to clamp work upon said bench.

At 4 is a bending leaf or apron hingedly attached to the bench at 5 andwhen suspended as shown in Figures 1, 3 and 4 having one of its surfaces6 flush with the top surface of said bench, I being the usual weightedbalancing arm for the said bending leaf or apron.

Hingedly mounted upon the front face of the bending rail 2, as the novelpart herein, in a machine for the purpose of forming joints, is a bar 8which shall be termed herein an abutment member, this being of anylength desired, the form thereof in cross section being substantially asillustrated in the figures, part of said member likewise being shown inperspective in Figure 1 0 1 The mounting for said member may be, forexample, one or more hinges one of which is indicated at 9 by which itmay be mounted upon said The point of the hinge 9 at the a shortdistance from the plane of the bench top, being in this instance adistance about equal to the thickness of the apron 4 plus the thicknessof the work A, said member being spaced from the rail 2 a distance,also, slightly greater than a double thickness of said work as will beunderstood later.

The member 8 is formed with an operating handle Land a suitable springfriction device at u maybe ailixed'to the rail 2to engage the handle tomaintain the member normally in the position shown in Figures 1, 2 and4.

To form a Pittsburgh joint it is required, of course, that a metal sheetat its edge must be twice folded upon itself in the form of a Z, and

this usually somewhat diflicult operation is quite simply produced onthe machine or apparatus as herein appointed.

In the practical operation the work is clamped upon the bench l by thenamed bending rail 2 with sufficient stock projecting across and beyondthe apron i to provide the final result. The work having been properlyadjusted and clamped the projecting portion is now acted upon byupwardly swinging the apron s, Figure 2, whereupon, the work is given anarcuate angular bend b over the margin of the rail 2, and said apronthen reaching a position at right angles to the plane of said rail 2,and at the same operation by crowding the work between itself and theabutment member 8 bends said work to form the extension 0, the saidmember 8 thus constituting an abutment for the purpose. The apron maynow be returned to its normal pendant position, whereupon the member 8is' swung forward to substantially the position shown in Figure 3, itsend surface 8' carrying the said extension over upon the initial bend b,any portion, as d, extending beyond the said initial bend I) beingforced upon the face of the apron l and, caused to take up a slightangle to said extension 0.

It is now apparent that the abutment member 8 if spaced sufficientlyfrom the rail 2 will admit of two thicknesses of the Work to lie betweensaid member and said rail and the spacing may be more or less asdesired, sufficient space being perfrom the clamping arrangement theextension (2 mitted, however, to admit of the entrance of companionmember between I) and c employed in creating a conduit within an elbow,see Figures 7 and 8, or other forms.

Having created the single fold shown in Figures 3 and 6 the work is nowplaced between suitable clamping devices such, for example, as the rail2 and table i, see Figure 4, and the whole collapsed into the Z form.And upon removal of the work will take up a slightly angular positionwith respect to 0, see Figure 7, and act as a guide for the namedcompanion portions of the said elbow or other conduit structure to becreated.

It is' noted that the extension d is bent at a slight angle to b, c inproducing the folded portion in Figure 3 by being forced upon the apron4, retaining that relation even under pressure of the rail 2 in Figure 4as evidenced in Figure '7.

"That is to say, the pressure of the rail in collapsing the folds b, 0does not necessarily occasion any change in the angle of d, that portionspringing back to its angular position after pressure is removed.

Figure 8 illustrates part of a conduit in the form of an elbow, in linewith the last above, wherein the parts A each operated upon as hereindescribed at each of its edges and afterward bent into curved form forelbow purposes, not new herein, and receive side members B, B forming acomplete conduit structure.

While the plane of the working face of the bending rail 2 may have anyother angle with respect to the top surface of the bench i an obtuseangle such as shown is preferable since the work in the form shown inFigures 3 and 6, whose bends b and 0 lie at an acute angle to the benchsurface is in better position to receive pressure thereon for collapsingpurposes, it being always "preferable, of course, that the work approachas much as possible a Z-form in order that pressure may be more easilyapplied thereto.

Again, the various elements of the machine structure may have positions,relatively, other than those shown as long as the several operationsupon the work provide the results required upon such work in producingthe final completed forms shown.

While the invention contemplates a type of apparatus wherein the apronis hingedly mounted as herein, said apron may perhaps be otherwisedisposed and operated while free to crown the work into the angle formedat the working faces of the rail and abutment member. Thus it is not thepurpose to be confined to the exact means shown for operating upon thework.

I claim:

1. In apparatus for bending sheet metal in forming Pittsburgh jointsincluding a support to receive the work, means to clamp the work uponsaid support, including arail to receive upon a face thereof part of thework, an apron hingedly mounted adjacent the support, and an abutmentmember hingedly mounted adjacent the face of the said rail adaptedtoswing between two positions with respect thereto and having a faceadapted to lie normally substantially at right angles to the plane ofsaid face of the rail, said apron in its hinging action adapted to bendthe work toward and against the named faces of the said abutment memberand said rail and together with said work fit into the angle made bysaid faces, said abutment member in a hinging action thereof adaptedupon removal of the apron from said angle to engage the work and doublesaid work upon itself.

2. In apparatus for bending sheet metal in forming Pittsburgh jointsincluding a support to receive the work, means to clamp the work uponsaid support, including a rail to receive upon a face thereof part ofthe work, an apron hingedly mounted adjacent the support and having awork engaging surface substantially flush with the work receivingsurface of the support, and an abutment member hingedly mounted adjacentthe face of the rail and normally substantially paralleling the latter,a face of the member having spaced relation to the plane of the workengaging face of the apron and that of the support and lyingsubstantially at right angles to the said face of the said rail, saidapron adapted in a swing thereof to lie within the angle formed by saidface of the member and that of said rail and to force into said angle anextension of work mounting on the support, said member adapted in ahinging action thereof to engage the said extension of the work anddouble it upon itself while abutting upon said rail.

3. Apparatus for bending sheet metal in forming Pittsburgh jointsincluding in its construction a support, a member thereon for receivinga sheet of metal against it, a hingedly mounted bending apron on thesupport adapted to engage and bend the metal to carry a part thereofupon said member, and an abutment member lying adjacent such member andhingedly mounted thereon and having a face to receive that part of themetal against it, bent up by said apron, said face of the abutmentmember in the hinging action of said abutment member adapted to doublesaid part of the metal upon that part so bent upon the described firstmember by said apron.

4. Apparatus for bending sheet metal in forming Pittsburgh jointsincluding in its construction a member to fix a sheet of metal inposition to be worked upon and for receiving the metal against it, ahingedly mounted bending apron adapted to engage and bend the metal tocarry a part thereof against said member, and a hingedly mountedabutment member lying at the first member and having a face disposedadjacent the work receiving face of said first member, and also adaptedto receive part of the metal against its said face, said face of saidabutment member adapted in a hinging action of the latter to double thesaid part of the metal upon that part lying upon said first member.

I Apparatus of the nature and for the purpose [angle to the plane of themetal to be processed,

if [a bending apron mounted to. swing about the rail and to engage andbend part of the metal over upon the said rail, an abutment portion atsaid rail mounted to swing and to'receive against it an extension ofsaid part of the metal so placed at the said rail, said abutment memberhaving a face adapted to engage and fold the said extenffsion upon andsubstantially paralleling said part so positioned upon said rail.

1 6. Apparatus of the nature and for the purpose l described includingin combination with a support having a surface for receiving upon itwork to: be processed, a bending rail lying adjacent the said surface ofthe support and also having a working surface, the same being inclinedat an acute angle to said surface of the support, and

a bending apron adjaicent both the surfaces adapted in a movementthereof to engage and bend the work at an acute angle towardthe saidsurface of the rail, an abutment member hingedly mounted adjacentthe-said surface of the rail and itself having a working face lyingnormally at an angle to the rails said surface, said member adapted toreceive an extension of the work against its working face in the namedaction of e the-apron, and said member adapted in a hinging actionthereof to engage and bend said extension ed, a rail at the supporthaving a surface inclined at an angle to the said surface of thesupport, a member hinged at the support having a surface substantiallyparalleling the said surface of the same, said member adapted to foldpart of the metal distant from the margin thereof upon the inclinedsurface of the rail, a hingedly mounted member at said rail, the samehaving a surface lying normally at an angle to the surface of the, railand also receiving part of the thus folded metal against it in theaction of the first named member, said surface in a hinging action ofsaid member adapted to fold the metal lying thereagainst upon thatportion of said metal abutting the inclined surface of the rail and toforce a free marginal portion of the metal upon the first named memberin the normal position of that member.

8. In an apparatus for use in forming joints, the combination with asupport, a rail cooperating therewith for clamping sheet metal workthereon and having a working surface lying at at obtuse angle to theworking surface of the support, and a bending apron hinged to saidsupport having an operating work engaging surface, of an abutment memberhingedly mounted in close proximity to said surface of said rail andhaving a surface disposed in spaced relation to both the hinge line ofsaid apron and the working surface of said support, said surface of saidabutment member adapted in the hinging action of the said apron toreceive against it a part of the sheet metal work carried by said apron,the latter also carrying'part of the work upon the rail adjacent theabutment member, and said surface of said abutment member in the hingingaction of that member adapted to be carried to a position substantiallyparallel to the named surface of the rail to fold the work upon itselfat said rail.

GEORGE EDWIN DEMMIN.

